I’ve been reading further into Albert Jack’s book It’s a Wonderful Word and where the word ‘marmalde’ comes from. There are two theories. The most popular story is that is comes from Marie malade (‘ill Mary’) referring to Mary, Queen of Scots in which she apparently used the spread to settle her stomach during seasickness. But the word probably doesn’t derive from this at all.
‘Marmaade’ was in use by 1480 according to the OED. If we look further, it is perhaps easy to see why the first theory has gained so much weight, as ‘mer’ means sea and ‘malade’ means sick. But the word actually comes from Portuguese ‘marmelada’, a name for a sweet paste or spread. In Portuguese, ‘quince’ is ‘marmelo’ which were imported as a luxury to Britain from the late fifteenth century. Quince was so expensive it was only used by royalty and the elite. As a result, Tudor cooks created a cheaper version using lemons and bitter Seville oranges that they called ‘marmalades’. Interestingly, the Tudors then cut it into slices and ate it as sweets which must have been quite sickly. The first marmalade factory was built in Dundee in 1797 and the cheaper version remained popular ever since, and began to be a popular spread of choice at breakfast time.